This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Still images and digital video are generally captured using sensor arrays. These arrays contain large numbers of light sensitive elements and corresponding electronics to produce digital values indicative of the amount of received light at each location on the array. In a CCD sensor, each sensor holds a charge, which is converted to a voltage, which is then converted to a digital value in a digital imaging system.
In most systems for still image and video capture, color filters are used to make individual sensors in the array sensitive to certain ranges of wavelengths of light. The most common sensors use filters to allow separate detection of light in the red, green, and blue portions of the visible spectrum. Digital values from groups of nearby sensors filtered for red, green, and blue light are generally used directly or interpolated to produce each RGB pixel value of an output image.
If a particular sensor in an array is defective, one or more of the red, green, or blue values for a pixel may be erroneous. In some cases, a sensor may be described as “dead,” and produce a minimum output regardless of the amount of incident light. In other cases, the sensor may be described as “stuck,” producing the maximum output regardless of the amount of incident light. Physical obstructions such as dust particles on the sensor may also cause suboptimal image data.
Pixel values from such defective sensors may differ significantly from those of neighboring pixels and produce a visible, objectionable defect in the image. It can therefore be desirable to apply image processing to detect pixel data produced by faulty sensors and substitute values based upon information from surrounding pixels to reduce the impact of the defect. The invention described herein addresses these and/or other problems.